The present invention relates to molded gaskets, and especially to high temperature-resistant molded plastic gaskets for use in connection with automotive engines and in other environments where similar service conditions are encountered.
A wide variety of gaskets have been suggested in the prior art for automotive and other uses. Some such gaskets have been molded of high temperature plastics and have used sealing beads to enhance their sealing characteristics. For example, in U.S. Pat. No. 4,817,969 a molded, fiber filled plastic gasket has sealing beads which are integrally formed with the gasket body. The bead is preferably trapezoidal in cross-section and extends above the surface of the main body a distance of from about at least five percent to about fifteen percent of the thickness of the main body. Desirably a pair of recesses are provided in the main body at the base of and immediately adjacent to each sealing bead. The recesses accommodate some flow of the resin forming the bead under high sealing loads to reduce the possibility of stress-cracking of the sealing beads.
It would be desirable to provide improved gaskets for sealing joints, such as joints in automotive engines, and in particular to provide molded plastic gaskets having improved, integrally formed beads which function to seal without requiring excessively high clamping loads and which are adapted for use in a wide variety of environments.